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Alternator voltage drop under load

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Old 04-16-2019, 10:58 PM
  #91  
Speedtoys
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Originally Posted by j.kenzie@sbcglobal.net
Jeff is correct. You can test the TPS function at the 35-pin connector at the ECU. Pin 2 to pin 18 IIRC. 0 ohms at idle, open circuit off idle. Again, with an intermittent problem, it may test OK one day and fail the next. I can't think of a provocative maneuver for this test, but maybe there is something suspicious that you will notice.
Good luck,
Dave
I can see taking the meaning of a "tight" idle switch engagement taken too far, and when everything is warm, it just wont go all the way to idle all of the time...one of the two cables might just be juuuuust a hair too short for "all conditions".

Old 04-16-2019, 11:12 PM
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Originally Posted by Speedtoys
I can see taking the meaning of a "tight" idle switch engagement taken too far, and when everything is warm, it just wont go all the way to idle all of the time...one of the two cables might just be juuuuust a hair too short for "all conditions".
That's what I was thinking. Maybe adjusted just on the edge of engaging, so mechanically it fails to engage on a different day or condition. Maybe just a little tweak on the switch position?
Thanks,
Dave
Old 04-16-2019, 11:47 PM
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Originally Posted by j.kenzie@sbcglobal.net
That's what I was thinking. Maybe adjusted just on the edge of engaging, so mechanically it fails to engage on a different day or condition. Maybe just a little tweak on the switch position?
Thanks,
Dave
Well, THAT usually doesn't act funny, more directly mechanical. They're never stiff, etc..fairly binary in adjustment.

But I should have also stated when setting the cables..which is part of the same larger procedure as Idle adjustment..either of the accel cables could be a hair over adjusted...and when a cable sheath of the quadrant is warm(er), just a tad too stiff to let that last 1/164th inch of extension happen to get the switch down to idle.
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Mrmerlin (11-30-2021)
Old 11-30-2021, 05:28 AM
  #94  
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Hey Merchauser did you ever figure out what was causing your issue? In your descriptions above you note voltage gauge behavior that some days when you turn something on, including go into reverse, the volt gauge lowers. My car does that also, including when I put into reverse. My volt gauge eventually winds up sitting on 12 and turning things on can make it go below....Just ran car on idle with everything on (headlights, fog lights, AC, fan on high, rear window on DE-ICE setting, windshield wipers and sitting at 13.8 at jump post...so plenty of power; vehicle was warm but not hot...it hadn't been run in several hours.

I don't have the stalling issues you are reporting but am interested if you figured out what was causing your voltage gauge impacts....I have an instant up/down relay for windows and when the volt gauge is reading low, the motors run slower and sometimes I see the relay fail to disengage and I have to hit the button (Hans' flat panel) to turn off.....when the gauge is running above 12 to near 13, external relay works fine. I'm going to clean the connections to it tomorrow but as the issue is coinciding with a low voltage read on the gauge hopefully if you've figured it out it could help me as well

Thanks
Matt
Old 11-30-2021, 08:47 AM
  #95  
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Originally Posted by 928NOOBIE
Hey Merchauser did you ever figure out what was causing your issue?
Thanks
Matt
Hi Matt,
My solution involved a very thorough cleaning of the CE panel, especially the connections related to the gauge. One of those chores that is tedious,
but I highly recommend you do it and do it the proper way; don't cheat or skimp. Make sure EVERY connection is tended to. Rennlist search will give
you plenty of info on best way to clean. I used emery paper, Dremel with wire wheel, and liberal amounts of Deoxit. You will be rewarded 10 fold.

I also replaced my battery ground strap and the ground strap at RH side of engine to chassis. Beyond that, I would clean your 14 pin connector, and
check the wire from the jump post to the alternator; they are often frayed and in poor repair. Best of luck!



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